Method of insulating electrical conductors.



J. A. HEANY.

METHOD OF INSULATING ELECTRICAL GONDUGTORS.

APPLICATION rum) rmm, 1913.

1,071,676. Patented Aug.26, 1913.

2 SHEETS-SHEET 1.

TE -E J. A. HEANY.

METHOD OF INSULATING ELECTRICAL OONDUGTORS.

APPLICATION FILED FEB. 4, 1918.

1,071,676. Patented Aug. 26, 1913.

2 BHEETB'SHBET 2.

,JOHN ALLEN HEAN Y, OF -WASHINGTON, DISTBICTLOFCOLUMBIA.

METHOD OF INSULATING ELECTRICAL CONDUCTORS.

Specification-of Letterslratent.

Application filed lebruary 4, 1913.

Patented Aug. 26,1913. serial-Nahum.

To all-whom, it may concem Be it known that 1, JOHN ALL-nNHEA-NY, acitizen of theiUnited statesyresiding iin the city of -Wa'shington,District of ()Ol'umbia,vhave invented certainhew and useful Improvementsin Methods of .Insulating Electrical Conductors; andI dohereby declarethe following to be a full, clear, and exact description oftheinvention, such as will enable others skilled in the art to which itappertains to make and use the same.

The invention relatesto a metliod of applying fibrous insulatingmaterial to conductorsrin therform of a smooth,'uniform, homogeneousfireproof or water-proof sheath of any desired'degree of thickness, andis especially applicable'forthe insulation of conducting wires, ribbonsand-the like with asbestos or similar fibrous material in the form ofrelatively short fibers, ordinarily incapable of being spun into threadsor yarns, so applied to the conductor -as to provide a regular anduniform covering-or sheath to produce a smooth surfaced in-' sulatedconductor of'uniform diameter'or thickness, possessing a substantiallyuni-v form insulating factor throughout.

iIt has beenproposed' heretofore to apply asbestos or similar materialto electrical conductors, as an insulatin 1nediu-rr1,-either in the formof spun threa s-oryarns made up of relatively long fibers, or,inthealternative,'t0 apply such fibrous material directly to the wire bymeans ofan axlhesivefthe fibers being distributed over the adhesivecoated wire and then matted down as'far as possible to produce anenveloping sheath. The first method involving theuse of spun threads oryarns has not proved altogether satisfactory, because of the fact thatshort fibers cannot be employed for the purpose, which renders itnecessary to use the relatively expensive long fibers, and furthermore,in the case of asbestos, it is practically impossible to produce aregular uniform thread or yarn even 'from the long fibers. Again, theuse of relatively hard spun threads or yarns as an insulating coveringhas been found ob'ectionable in thatdt is difiicult to effect ahomogeneous, uniform sheath or covering, inasmuch as the spaces of"- thesheath irregular. The second method "referred to, namely coating theconductor with the fiber or flock applied directly to the wire-throughthe agenc -of an adhesive is likewise objectionable or the reason thatit i is impossible to produce a uniform coating, either as to thicknessor insulating qualities. 7

The present invention is designed to overcome all of the objections anddifliculties hereinbefore referred to, and at the same time to admit ofthe employment of the rela tively cheap, short fibers of asbestos,cotton, jute, hemp, or other suitable fibrous material, to produce ahighly eflicient, uniform and homogeneous insulating sheath upon wiresof even the smallest diameter, by first applying the fibrous material inthe form of a matted or feltedcoveringto a relatively smallthread orfilamentary body, and 'then applying the thread or filamentary body thuscoated: to the conductor to be insulated, preferably by winding thefiber-coated thread about the conductor and working the same-downtoauniform'thickness, as will be hereinafter more particularly de scribed.

A -simple for-m of apparatus for carrying out theimetholdis illustratedin the accompanying drawings, in which Figure 1 is a diagrammaticrepresentation of mechanism for the preliminary coveringzo'f a thread or-filamentary body with the *fibnous insulating material. Fig. 2issasimilar view of apparatus for applying the=fiber-coated thread tothe conductor.

Fig. 3 shows-a section of the conductor with the insulating materialbeing applied thereto.

Z-Referring'to Fig. -1 of the drawings, '1 indicates a ball, .spoolor00p of thread-or yarn which may be of any desired'size, but which ispreferably as fine or of as small diameter as the'exigencies of the-workwill permit. Said ball or cop 1 is mounted upon a, spindle 2,- whichmay, if desired, be rotatedin a direction at right angles to its axis,but which as shown is capable of r0- tationmbout its longitudinal axis.As the thread or yarn is. paid ozfi' of the ball or cop 1, it passesover and around a tension roller 3,:thence around a roller 4 which isimmersed in a tank 5 containing an adhesive, such as water, glue, paste,albumen, sodium silicate, or any other gelatinous or sticky substance,appropriate to coat the thread or yarn to cause fibrous'materials comingin contact with the thread or yarn to adhere thereto. From the adhesiveapplying roller 4, the thread passes directly over the dofl'er of acarding machine or the like, said dofl'er being represented as a belt 6of usual and appropriate form, passing over a roller 7 and serving todraw out the elements of the fibrous material in lines parallelwith therun of the dofl'er belt, as will be understood. Beyond the dofl'er 6,the thread passes around a pulley 17 mounted on the lateral arm of arotary flier 8 which in turn is rotated on its horizontal axis by apulley 12 by means of a belt 13, the flier 8 and pulley 12 beingjournaled in a suitable bearing 13. Carried by the flier 8 is a spindle9 adapted to receive a spool 18 upon which the fiber-coated thread iswound, rotary motion being imparted to said spool 18 by means of a bevelpinion 10 on spindle 9, which meshes with a bevel gear 11 mounted on thespindle 14 concentric with the axis of flier 8, to the outer end ofwhich spindle 14 is attached a brake drum 15 about which is loopedseveral turns of a cord or rope 16, anchored at its upper ends to astationary abutment and provided at its lower looped end with a pendentweight 16, the parts being so disposed that as the flier rotates aboutits horizontal axis, the coaction of pinion 10 with gear 11 will causethe spindle 9 to rotate and wind the thread on the spool 18. The actionof the brake drum 15 and its associated cord and weight 16 and 16 admitsof the spool 18 being rotated with just suflicient force to wind thethread regularly and evenly on the spool 18. By regulating the amount ofthe weight 16', the degree of tension on the spool rotating mechanismmay be nicely adjusted.

The apparatus as thus described affords a simple and eficient means forcarrying out the first step of the method involved in the presentinvention, to wit, the preparation of the fibrous material to form themain element of the insulating sheath as a loosely matted or felted masswound about the relatively light foundation thread for yarn, andpreferably secured to the latter by means of a suitable adhesive. Itwill be understood that the mechanism is merely exemplary and that theoperations performed thereby can be produced by other forms ofmechanism, or if desired, even by hand.

The operation of the apparatus is as follows: When the thread or yarn isdrawn ofl of the cop 1 and passes around the roller 3 and thence throughthe other parts ,of the mechanism to the spool 18, the thread is.

given a rapid rotation about its longitudinal axis, so that when thethread passes in contact with the dofl'er belt 6, it takes up thestraightened threads or fibers of the material carried by the belt andcauses said fibers to be wrapped about its body in a loosely mat-tedcondition, the fibers however adhering to the thread, first because ofthe twisting action imparted thereto by the rotation of the thread, andsecond, because of the cementing effect of the adhesive applied to thesurface of the thread by the roller 4. The travel of the thread throughthe machine may be quite rapid, and by regulating the relative speeds ofthe dofl'er 6 and the flier 8, any desired thickness of the fibrousmaterial wound and matted on the thread may be readily accomplished, Asthe thread leaves the dofl'er 6, the fibrous coating thereon is more orless flufiy and irregular in appearance, but is nevertheless distributedover the surface of the thread with exceptional regularity, and inpassin around the guide roller 17 on the flier head 8, the fibrouscoating is more or less compacted, so that when the fiber coated threadis ultimately wound upon the spool 18, it can be laid up in compactregular convolutions. After all of the thread has been unwound from thecop 1, coated with the adhesive and fibrous material and wound upon thespool 18, the latter is removed from the flier head for subsequent useand the operation repeated with another supply of thread and an emptyspool 18.

When this or a similar apparatus is employed for coating the foundationthread of filament with asbestos, it "is found convenient and preferableto use the cheap, shortfibered asbestos of commerce, which lends itselfreadily to the carding operation of an ordinary carding machine and isdelivered to the dofier in a multiplicity of short filaments which areengaged by the rotating thread and wound and matted thereon in arelatively loose but uniform mass. The thickness of the covering ofasbestos fiber on the thread will, as heretofore indicated, depend uponthe width of the dofi'er and the relative speeds of travel of thedofi'er and the thread. If it is desired to apply a substantially thinbut regular coating of asbestos to the thread, a comparatively narrowdofi'er belt may be employed, or the thread may be fed across the sameat a relatively higher rate of speed and correspondingl if a thicker andheavier coating of asbestos or the like is desired, a wider dofi'er beltmay be employed, or the dofl'er may be driven at a higher rate of speed,or in the alternative, the thread may be fed more slowly across thedofl'er. What is true of the asbestos fiber, applies likewise to otherfibrous materials which may be employed, and in any case, the result ofthe operations is a relatively small foundation thread or yarn of anyappropriate material completely covered with a mass of twisted andmatted fibers, uniformly distributed over the surface of the thread andaffixed to the latter by a suitable adhesive, which fibercoated threadis wound upon-ass 01 for subsequent use. If it .is foundzun sirable toimpart anyextra. twist to the-foundation thread, but nevertheless tocause. the-thread to take up the fibers from the dofie-r and dispose thesame in auniform-mattcd layer about its surface, the. spindle 2 of thecop 1 may be given a. rotary motion in. theses-1e diireotiomand at thesame speed as. the! flier head 8, so that the whole bodyof the threadand its supports will; be rotated: without twisting any intermediatePOEtiQHLOi said thread.

To apply the fiber-coated thread to its intended purpose, to. wit, asaninsulating sheath or covering for conductors, an apparatus such asillustrated in Fig. 2 may be conveniently employed, said apparatuscomprising a reel 19 upon which the conductor in the form of'a wire,ribbon or the like is wound, a pair of straightening and guiding rollers21 adjacent the reel, an adhesive applying roller 22 mounted in areceptacle 23 over which roller 22 the wire passes, a ro" tary flier 24journaled in a suitable bearing 25 provided with a longitudinalopeningthrough which the wire travels, said flier having one or morestuds or pintles 24 upon which are secured one or more spools 18'containing the fiber-coated thread, prepared in accordance with thepreliminary method hereinbefore described. The flier 24 is preferably inthe form ofa pulley driven by a belt 26, as will be understood. Beyondthe flier 24, the conductor 20 having the fibercoated thread woundthereon in spiral convolutions passes over a roller 27'molmted in areceptacle 28 which contains a coating composition and which appliessuch composition to the fiber-coated thread. If it is do--- sired towater-proof the insulating sheath, the composition contained in thereceptacle 28 may consist of paint or varnish, composed of asphaltum, orgums, or resins, or any suitable synthetic plastic resistant substance.If it should be desired to render the insulation fire-proof, then thecomposition applied by roller 27 may consist of sodium silicate,silicate of lime, kaolin, a metallic oxid, such as oxid of alumina, or alime product, such as sulfate of lime, or if desired, any admixture ofthe foregoing ingredients worked up to a gluey cohering consistency andwhich will ultimately form with the fibercoated thread a smooth,uniform, coherent, flexible sheath. After leaving the compositionapplying roller 27, the coated wire is passed through a series ofsmoothing and finishing devices, which may be of any preferred form andwhich are effective to smooth and reduce the composite coating to ahomogeneous layer of uniform thickness and continuity. As shown in thedrawings, said smoothing and finishing devices comprise a series ofrotary disks 29 through the center of which the covered: wire passes,which disks are driven byabelts=30;'. Upon the rear faceioi each diskis-mounted a pair of bell crank levers 31 having-attheir free endsclamping jaws 34-Whl0ha surround the conductor and are held in contacttherewith by means ofpressure springs 33'dispcsed bet-ween.- the outerends ofithe bellcranknles vers and the carryingdisks. The. circularopeninge-fonmedby the mating grooves in. the adjacent faces ofthejaws34=are=preferably of successively decreasing diameter-in the severaldevices so that as these jaws are carried around the wire by themovement of the rotary disks, they successively smooth, compact andreduce-thecoat-ing on the con.- ductor to am enveloping sheath or layerthat is uniform throughout and presents a closely adherent shell-dikesheath for-the conductor. After. passing the smoothing andsurfacefinishingdevices, thecovered conductor may be subjectcd. totheinfluence of heat or moistune, .as. the case-.may be, for the purposeof setting the coating, as for-example, by means of the burner orspraying device 40-. The finished wire then passes between guide roll1-ers 41 to a storage reel or bobbin. 42;

If desired, the foundation thread carrying the fibrous material may beremoved. from the sheathbeforegthe final finishing operation'byssubjecting the conductor have ing-the fiber-coated. thread woundthereon, to suflicient heat towincinerate thethU8fld1 like core, withouthowever disturhin =the .rclationof'the-eoating fibers, .afterich' theregular impregnating and-finishingopera.- tions. can: be performed.Of'course, the -removal of the core is possible only in cases;

where the fiber coating the thread-like core would not itself bedestroyed by the core re-movin agent. Likewise, if it is founddesirable,t e thread-like core may be rendered fire-proof andwater-proof, or it may be initially formed of fire-proof or water-proofmaterial, such as cellulose, artificial fiber or the like.

By the application of the novel method hereinbefore disclosed, aconductor of any shane or size may be covered in whole or in part withan efiicient sheath of effective insulation, either fire-proof orwater-proof in character and of any desired degree of thickness, andwhile the initial fiber coating applied to the foundation thread orfilament is flufl'y and apparently, but not actually irregular in itsdisposition on the foundation thread, the ultimate insulating sheath isextremely compact and homogeneous and uniform in disposition andinsulating properties, so as to more nearly resemble a coating ofplastic material rather than a fibrous sheath. An insulating sheath ofthis character is especially eflicacious for conductors to be wound incoil form on electrical apparatus in which it is desired to have thecon- 'volutions as close to each other as possible,

consistenhwith the high degree of insulation which the cellularcharacter of the fibrous material aflords.

What I claim is 1. The method of insulatin conductors, which consists incovering a t read or filamentary body with a coatin of fibers, applyingthe fiber-coated threa to the surface of the conductor, and reducing thefibercoated thread to a layer of substantially uniform thickness.

2. The method of insulating conductors, which consists in coatin a.thread or filamentary body with an a esive, then with a sheath offibers, applying the fiber-coated thread to the surface of the conductorand reducing the fiber-coated thread to a layer of substantially uniformthiclmess.

3. The method of insulatin conductors, which consists in rotating a tread in contact with a body of fibrous material to coat the thread withfibers, applying the fibercoated thread to the surface of the conductor,and reducing the fiber-coated thread to a layer of substantially uniformthickness.

4. The 'method of insulatin conductors,

which consists in rotating a t read in contact with a bod of fibrousmatefial to c at the thread with fibers, winding the fi ercoated threadabout the conductor, and reducing the fiber-coated thread to a layer ofsubstantially uniform thickness.

5. The method of insulatin conductors, which consists in treating a reador filamentary body with an adhesive or binder, coating the thread thustreated with a body of loose fibers twisted and matted thereon,

applying the fiber-coated thread to :the surfaceof the conductor, andreducin' the fibercoated thread to a layer of su tantially uniformthickness.

'6. The method of insulating conductors, which consists in coating athread with an adhesive or binder, rotating the thread in contact with abody of loose fibers'to coatthe thread with said fibers, winding thefiber-coated thread about the conductor, im-

pregnating the winding with a' suitable binder, and finally reducing thecoating to the desired thickness.

(7. The method of insulating conductors, which consists in carding orstraightening a mass of loose fibrous material, applying saidstraightened fibers in a twisted and matted layer about an adhesivecoated thread, winding said fiber-coated thread .upon the conductor, andreducing the fiber-coated thread to a layer of substantially uniformthickness. 8. The method of insulating conductors, which consists incarding or straightening a mass of loose fibrous material, applying saidstraightened fibers in a twisted and layer about an adhesive coatedthread, winding said fiber-coated thread upon the conductor,impregnating the fibrous coating of the conductor with a binder, andfinally smoothing and finishing the impregnated coating.

In testimony whereof I aflix my signature, in presence of two witnesses.

JOHN. ALLEN HEANY;

Witnesses:

An'rmm L. BRYANT, CHAS. J. ONEILL.

